Organic binders for composite fiber products such as fiberglass insulation are moving away from traditional formaldehyde-based compositions. Formaldehyde is considered a probable human carcinogen, as well as an irritant and allergen, and its use is increasingly restricted in building products, textiles, upholstery, and other materials. In response, binder compositions have been developed that reduce or eliminate formaldehyde from the binder composition.
One type of these formaldehyde-free binder compositions rely on esterification reactions between carboxylic acid groups in polycarboxy polymers and hydroxyl groups in alcohols. Water is the main byproduct of these covalently crosslinked esters, which makes these binders more environmentally benign, as compared to traditional formaldehyde-based binders. However, these formaldehyde-free binder compositions also make extensive use of non-renewable, petroleum-based ingredients. Thus, there is a need for formaldehyde-free binder compositions that rely less on petroleum-based ingredient.
As an abundant and renewable material, carbohydrates have great potential to be an alternative to petroleum-based binders. Carbohydrates are already used as a component of some types for binders, such as Maillard binders that contain reaction products of reducing sugar carbohydrates and amine reactants. However, many types of carbohydrate-containing binders tend to become brittle when cured and form excessive particulates when the insulation is folded or compressed. Some carbohydrate-containing binders are also prone to accelerated degradation in humid environments and thus require additional conditioning and additives to improve their moisture/water resistance. Thus, there is a need to improve the stability and water resistance of carbohydrate-containing binder compositions to levels that are similar to or better than those of conventional, petroleum-based binder compositions. These and other issues are addressed in the present Application.